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United States Patent | 6,233,232 |
Chau ,   et al. | May 15, 2001 |
The present invention provides a modular architecture for connecting a plurality of telephone lines to a computer network. The invention binds a plurality of network access servers together so that they form a single system image to clients dialing into the plurality of network access servers. The invention operates by providing a tunneling mechanism for communication between the network access servers. The tunneling mechanism facilitates packet re-forwarding so that a call dialed into a physical port in a network access server can be re-forwarded through a logical port in another network access server. This allows a call to be routed through a physical port in a network access server even if no logical port is available in the network access server. Packet re-forwarding also allows multilink connections through physical ports in multiple network access servers to be routed through a single logical port in a network access server. Packet re-forwarding also provides support for spoofing; if the telephone line is torn down during spoofing, the logical port is maintained so that the connection may be reestablished through a physical port in another network access server. Finally, the present invention supports authentication across multiple network access servers using a security server, by allowing the network access servers to share authentication information.
Inventors: | Chau; Wing Cheong (Los Altos Hills, CA); Leu; Darren (San Jose, CA); Liu; Tze-jian (Cupertino, CA); Nilakantan; Chandy (Cupertino, CA); Pao; Jeffrey Kaiping (San Jose, CA); Sun; Tsyr-Shya Joe (Milpitas, CA); Tai; Wayming Daniel (Cupertino, CA); Wang; Xiaohu (Milpitas, CA) |
Assignee: | 3Com Corporation (Santa Clara, CA) |
Appl. No.: | 835534 |
Filed: | April 8, 1997 |
Current U.S. Class: | 370/352; 370/351 |
Intern'l Class: | H04L 012/66 |
Field of Search: | 370/237,235,352,355,351 379/93.31,93.32,90.01 709/249 |
5058108 | Oct., 1991 | Mann | 370/409. |
5631897 | May., 1997 | Pacheco | 370/237. |
5761281 | Jun., 1998 | Baum | 379/93. |
5802306 | Sep., 1998 | Hunt | 370/245. |
5841842 | Nov., 1998 | Baum | 379/93. |
5870386 | Feb., 1999 | Perlman | 370/256. |
5918019 | Jun., 1999 | Valencia | 709/227. |
5983282 | Nov., 1999 | Yucebay | 709/249. |